Can't Compete On Dung? Try Mating On Apple Pomace

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ScienceDaily (June 27, 2009) — In the mating world of yellow dung flies, large, brawny males almost always get the girl. However, a new study suggests that smaller males rule if presented with an opportunity to woo females when they are not hanging out on cow dung. It is the first time alternative male reproductive strategies have been observed in this species.

In a study published in the June 24 Proceedings of The Royal Society B, a group of Syracuse University (N.Y.) undergraduate students found that small male dung flies, which are traditionally unsuccessful at finding and keeping mates on dung pats, successfully mated with females feeding on composting apple pomace. In fact, large males were generally absent from the pomace mounds.
"This is a new chapter in the story of yellow dung flies," says Scott Pitnick, professor of biology in SU's College of Arts and Sciences. "No one has carefully studied this species off the dung. Small male dung flies can't compete with their larger counterparts on the dung, so in this case, they developed a different tactic to successfully pass their genes to the next generation."
Pitnick co-authored the study with the students. The students were enrolled in an advanced biology course designed to teach them to conduct original scientific research. Pitnick co-teaches the course with J. Albert C. Uy. As part of the course, the students were tasked with designing a study around the size and mating success of yellow dung flies.
"After we made our initial field observations for the class assignment, we could tell from our professors' reactions that our discovery was a piece of important information in the field," says Stephen Maheux '09, a biology major who graduated in May. "The course was designed to teach us how to be biologists; as such, we made a unique observation that ultimately resulted in a publication."
Until now, it was thought that yellow dung flies mated almost exclusively on manure. Females are drawn to the dung only when they are ready to mate. Little is known about the feeding habits of females when they are not at the dung pats, Pitnick says. On the other hand, males were thought to hang out almost exclusively around the manure, awaiting the arrival of the females. Competition on the dung among males is fierce and can result in injury or death to smaller males as well as females caught up in the struggle.
But, on Toad Hollow Farms in Nedrow, N.Y., the students noticed large numbers of females feeding on apple pomace in a field adjacent to the cow pasture where they were observing flies on dung pats. Much to the students' surprise, the females were frequently mating on the pomace, and with males that were significantly smaller in size than those found in the cow pasture. Furthermore, none of the sexually aggressive behaviors normally observed on the dung pats occurred on the pomace.
Owned by Bill Guptill, Toad Hollow Farms produces natural compost made from manure, leaf and yard waste, and fruit and vegetable waste from grocers in and around Central New York. Apple pomace is the pressed pulp that remains after juicing. The students' initial observations suggested that the availability of the pomace seemed to provide male dung flies with alternative mating opportunities.
Maheux and biology major Kali Henn, who will be a senior in the fall, continued working with Pitnick after the class concluded to collect and analyze additional data, re-confirm the initial class results, and help write the manuscript that was submitted for publication to The Royal Society.
"The class focuses on enabling students to experience the research process—from formulating questions and making the observations to designing the experiments, analyzing the data and writing the final manuscript," Pitnick says. "In this case, what started as a class exercise ended up as a significant finding in this field."
Adapted from materials provided by Syracuse University.

Evidence Of Memory Seen In Songbird Brain

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ScienceDaily (June 27, 2009) — When a zebra finch hears a new song from a member of its own species, the experience changes gene expression in its brain in unexpected ways, researchers report. The sequential switching on and off of thousands of genes after a bird hears a new tune offers a new picture of memory in the songbird brain.

The finding, detailed this month in the Proceedings of the National Academy of Sciences, was a surprise, said principal investigator David Clayton, a professor of cell and developmental biology at the University of Illinois. He and his colleagues had not expected to see so many genes involved, and thought that any changes in gene activity after a bird heard a new song would quickly dissipate.
The new experiments uncovered three distinct profiles of gene expression in the brain. One is typical of a bird sitting alone in silence. A second profile appears quickly just after a bird hears a recorded song – but only if the song is new to the bird. A third profile then emerges 24 hours later, after the song has become familiar.
"I can tell you whether the bird has heard a particular song before or not just by looking at the molecular assay," Clayton said.
In the study, each bird was kept in quiet isolation overnight before it heard a recording of a new song. The recording was then repeated every 10 seconds for up to three hours.
"The most important thing in its whole life is the sound of another bird of its species singing," Clayton said.
"And what we found is that 24 hours after the experience its brain is still trying to make sense of what it heard."
The new study took a broad snapshot of gene activity in the brain. Using DNA microarray analysis, the researchers measured changes in levels of messenger RNAs in the auditory forebrain of finches exposed to a new song. These mRNAs are templates that allow the cell to translate individual genes into the proteins that do the work of the cells. Any surge or drop in the number of mRNAs in brain cells after a stimulus offers clues to how the brain is responding.
Some genes were upregulated within 30 minutes of exposure to a new song, the researchers found, and these included a lot of transcription factors that modulate the activity of other genes. Many other genes were downregulated, including those that code for ion channel proteins, which allow ions to flow into the cell. This could be one way that the brain dampens its response to a powerful stimulus, protecting itself from too much disturbance, Clayton said.
"Whenever something unexpected and different comes along, such as the song of a new bird in the neighborhood, it's going to deform the listening bird's neural network," Clayton said. "And so the system has to basically absorb some of that, make some changes and not be overwhelmed by it. If you push the system around too much, cells die."
On the other hand, if the system were completely resistant to disturbance, no memory would form, he said.
Twenty-four hours after the initial stimulus, the pattern of activated genes was entirely different from that of the initial response, regardless of whether the bird heard the song again on day two or not, Clayton said. Those genes that were originally upregulated or downregulated had returned to baseline, and a new network of genes was engaged. A major focus of this new network appears to be the regulation of energy metabolism. This suggests a lot is still going on in the brain, Clayton said.
"It's like we've lifted the hood and we're seeing that these things are just chugging away," Clayton said. "The bird had this one day of experience and a day later the brain is in a different state. It's still in high gear. It's still processing stuff. It's still reverberating and echoing.
Journal reference:
Shu Dong, Kirstin L. Replogle, Linda Hasadsri, Brian S. Imai, Peter M. Yau, Sandra Rodriguez-Zas, Bruce R. Southey, Jonathan V. Sweedler, and David F. Clayton. Discrete molecular states in the brain accompany changing responses to a vocal signal. PNAS, published 18 June 2009, DOI: 10.1073/pnas.0812998106
Adapted from materials provided by University of Illinois at Urbana-Champaign.

Boy Or Girl? In Lizards, Egg Size Matters

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ScienceDaily (June 22, 2009) — Whether baby lizards will turn out to be male or female is a more complicated question than scientists would have ever guessed, according to a new report published online on June 4th in Current Biology. The study shows that for at least one lizard species, egg size matters.

"We were astonished," said Richard Shine of the University of Sydney. "Our studies on small alpine lizards have revealed another influence on lizard sex: the size of the egg. Big eggs tend to give girls, and small eggs tend to give boys. And if you remove some of the yolk just after the egg is laid, it's likely to switch to being a boy, even if it has female sex chromosomes; and if you inject a bit of extra yolk, the egg will produce a girl, even if it has male sex chromosomes."
In many animals, the sex of offspring depends on specialized sex chromosomes. In mammals and many reptiles, for instance, males carry one X and one Y chromosome, while females have a pair of X chromosomes. In contrast, animals such as alligators depend on environmental cues like temperature to set the sex of future generations.
The new findings add to evidence that when it comes to genetic versus environmental factors influencing sex determination, it doesn't have to be an either/or proposition. In fact, Shine and his colleagues earlier found in hatchlings of the alpine-dwelling Bassiana duperreyi that extreme nest temperatures can override the genetically determined sex, in some cases producing XX boys and XY girls. His group had also noticed something else: large lizard eggs were more likely to produce daughters and small eggs to produce sons.
Despite the correlation, Shine said he had assumed that the association was indirect. In fact, his colleague Rajkumar Radder conducted studies in which he removed some yolk from larger eggs, more likely to produce daughters, to confirm that assumption.
"We were confident that there would be no effect on hatchling sex whatsoever," Shine said. "When those baby boy lizards started hatching out, we were gob-smacked."
Shine thinks there will be much more to discover when it comes to lizard sex determination.
"I suspect that the ecology of a species will determine how it makes boys versus girls, and that our yolk-allocation effect is just the tip of a very large iceberg," he said.
The authors include Rajkumar S. Radder, University of Sydney, Australia; David A. Pike, University of Sydney, Australia; Alexander E. Quinn, University of Canberra, Australia; and Richard Shine, University of Sydney, Australia.
Journal reference:
Rajkumar S. Radder, David A. Pike, Alexander E. Quinn, and Richard Shine. Offspring Sex in a Lizard Depends on Egg Size. Current Biology, 2009; DOI: 10.1016/j.cub.2009.05.027
Adapted from materials provided by Cell Press, via EurekAlert!, a service of AAAS.

Mate Selection: Honesty In Advertising Pays Off

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ScienceDaily (June 19, 2009) — Throughout the animal kingdom brilliant colors or elaborate behavioral displays serve as "advertisements" for attracting mates. But, what do the ads promise, and is there truth in advertizing? Researchers at Yale theorize that when males must provide care for the survival of their offspring, the males' signals will consistently be honest — and they may devote more of their energy to caring for their offspring than to being attractive.

The idea that males showcase their best qualities to attract females for mating isn't a new one, nor is the idea that they might be deceptive in what they are promoting. Instead, the new findings better predict the requirement for honesty in advertising as a function of the male's suitability for parenting, according to Natasha Kelly, a graduate student in ecology and evolutionary biology at Yale and lead author of the study.
The peacock's ornate fanned tail — or the primping and posturing of a guy in a bar — are "advertisements" or mating displays that take substantial energy to maintain. When a male's energy is heavily focused on keeping up his appearance, he may have little energy to devote to caring for offspring. But that may be okay, say the researchers — in species where he does not really need to tend to the kids.
Previous research suggested that, under certain circumstances, males could be dishonest about their parenting skills and still have high reproductive success. This new model, now appearing in the online version of the Proceedings of the Royal Society B, examines the reliability of males' mating signals when they must care for offspring — an aspect that was missing in earlier studies.
There are many species in which males could, but do not have to, provide parental care — because females will pick up the slack. The Yale researchers focused on those species, like stickleback fish, where females cannot pick up the slack and males who do not provide care risk the survival of their offspring.
"This new work shows that when males can not escape the cost of failing to provide care, their advertisements will tend to tend to reliably indicate how much care they will provide," said senior author Suzanne Alonzo, assistant professor of ecology and evolutionary biology at Yale.
"The qualifier in this case is where males are obligated to provide care," said Kelly. "In that case, the quiet guy in the corner might be giving the more reliable advertisement for fatherhood."
The National Science Foundation and Yale University funded this research.
Journal reference:
Kelly et al. Will male advertisement be a reliable indicator of paternal care, if offspring survival depends on male care? Proceedings of The Royal Society B Biological Sciences, 2009; DOI: 10.1098/rspb.2009.0599
Adapted from materials provided by Yale University, via EurekAlert!, a service of AAAS.

Humans More Related To Orangutans Than Chimps, Study Suggests

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ScienceDaily (June 18, 2009) — New evidence underscores the theory of human origin that suggests humans most likely share a common ancestor with orangutans, according to research from the University of Pittsburgh and the Buffalo Museum of Science. Reporting in the June 18 edition of the Journal of Biogeography, the researchers reject as "problematic" the popular suggestion, based on DNA analysis, that humans are most closely related to chimpanzees, which they maintain is not supported by fossil evidence.

Jeffrey H. Schwartz, professor of anthropology in Pitt's School of Arts and Sciences and president of the World Academy of Art and Science, and John Grehan, director of science at the Buffalo Museum, conducted a detailed analysis of the physical features of living and fossil apes that suggested humans, orangutans, and early apes belong to a group separate from chimpanzees and gorillas. They then constructed a scenario for how the human-orangutan common ancestor migrated between Southeast Asia—where modern orangutans are from—and other parts of the world and evolved into now-extinct apes and early humans.
The study provides further evidence of the human-orangutan connection that Schwartz first proposed in his book "The Red Ape: Orangutans and Human Origins, Revised and Updated" (Westview Press, 2005).
Schwartz and Grehan scrutinized the hundreds of physical characteristics often cited as evidence of evolutionary relationships among humans and other great apes—chimps, gorillas, and orangutans—and selected 63 that could be verified as unique within this group (i.e., they do not appear in other primates). Of these features, the analysis found that humans shared 28 unique physical characteristics with orangutans, compared to only two features with chimpanzees, seven with gorillas, and seven with all three apes (chimpanzees, gorillas, and orangutans). Gorillas and chimpanzees shared 11 unique characteristics.
Schwartz and Grehan then examined 56 features uniquely shared among modern humans, fossil hominids—ancestral humans such as Australopithecus—and fossil apes. They found that orangutans shared eight features with early humans and Australopithecus and seven with Australopithecus alone. The occurrence of orangutan features in Australopithecus contradicts the expectation generated by DNA analysis that ancestral humans should have chimpanzee similarities, Schwartz and Grehan write. Chimpanzees and gorillas were found to share only those features found in all great apes.
Schwartz and Grehan pooled humans, orangutans, and the fossil apes into a new group called "dental hominoids," named for their similarly thick-enameled teeth. They labeled chimpanzees and gorillas as African apes and wrote in Biogeography that although they are a sister group of dental hominoids, "the African apes are not only less closely related to humans than are orangutans, but also less closely related to humans than are many" fossil apes.
The researchers acknowledge, however, that early human and ape fossils are largely found in Africa, whereas modern orangutans are found in Southeast Asia. To account for the separation, they propose that the last common human-orangutan ancestor migrated between Africa, Europe, and Asia at some point that ended at least 12 million to 13 million years ago. Plant fossils suggest that forests once extended from southern Europe, through Central Asia, and into China prior to the formation of the Himalayas, Schwartz and Grehan write, proposing that the ancestral dental hominoid lived and roamed throughout this vast area; as the Earth's surface and local ecosystems changed, descendant dental hominoids became geographically isolated from one another.
Schwartz and Grehan compare this theory of ancestral distribution with one designed to accommodate a presumed human-chimpanzee relationship. They write that in the absence of African ape fossils more than 500,000 years old, a series of "complicated and convoluted" scenarios were invented to suggest that African apes had descended from earlier apes that migrated from Africa to Europe. According to these scenarios, European apes then diverged into apes that moved on to Asia and into apes that returned to Africa to later become humans and modern apes. Schwartz and Grehan challenge these theories as incompatible with the morphological and biogeographic evidence.
Paleoanthropologist Peter Andrews, a past head of Human Origins at the London Natural History Museum and coauthor of "The Complete World of Human Evolution" (Thames & Hudson, 2005), said that Schwartz and Grehan provide good evidence to support their theory. Andrews had no part in the research, but is familiar with it.
"They have good morphological evidence in support of their interpretation, so that it must be taken seriously, and if it reopens the debate between molecular biologists and morphologists, so much the better," Andrews said. "They are going against accepted interpretations of human and ape relationships, and there's no doubt their conclusions will be challenged. But I hope it will be done in a constructive way, for science progresses by asking questions and testing results."
Schwartz and Grehan contend in the Journal of Biogeography that the clear physical similarities between humans and orangutans have long been overshadowed by molecular analyses that link humans to chimpanzees, but that those molecular comparisons are often flawed: There is no theory holding that molecular similarity necessarily implies an evolutionary relationship; molecular studies often exclude orangutans and focus on a limited selection of primates without an adequate "outgroup" for comparison; and molecular data that contradict the idea that genetic similarity denotes relation are often dismissed.
"They criticize molecular data where criticism is due," said Malte Ebach, a researcher at Arizona State University's International Institute for Species Exploration who also was not involved in the project but is familiar with it.
"Palaeoanthropology is based solely on morphology, and there is no scientific justification to favor DNA over morphological data. Yet the human-chimp relationship, generated by molecular data, has been accepted without any scrutiny. Grehan and Schwartz are not just suggesting an orangutan–human relationship—they're reaffirming an established scientific practice of questioning data."
Journal reference:
John R. Grehan1 and Jeffrey H. Schwartz. Evolution of the second orangutan: phylogeny and biogeography of hominid origins. Journal of Biogeography, 2009 DOI: 10.1111/j.1365-2699.2009.02141.x
Adapted from materials provided by University of Pittsburgh.

Hunters Are Depleting Lion And Cougar Populations, Study Finds

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ScienceDaily (June 18, 2009) — Sport hunters are depleting lion and cougar populations as managers respond to demands to control predators that threaten livestock and humans, according to a study published in the June 17 issue of PLoS One. The study was led by Craig Packer, a University of Minnesota professor and authority on lion behavior, who worked with an international team of conservationists.

The study looked at numbers of lions and cougars killed by hunters over the past 15 to 25 years in Africa and the western United States. The analysis suggested that management agencies often adjusted quotas to control rather than conserve the big cats in areas where humans or livestock were threatened.
Sport hunting takes a significant toll on these large feline species because replacement males routinely kill their predecessors' cubs to improve their mating opportunities. (Killing cubs forces female lions into estrus or "heat.") The team of scientists confirmed this effect by comparing the impact of hunting on populations of lions, cougars and leopards with its impact on black bear populations because male black bears do not routinely kill infants of other males.
Lion and cougar populations have suffered the greatest decline in African countries and U.S. states where sport hunting has been most intense over the past 25 years, the researchers found. Leopards were not as affected as lions and cougars, most likely because they benefited from reduced numbers of lions. Black bears, by contrast, appear to be thriving despite the thousands of bears killed by hunters.
The study results point to the need for new approaches to protect humans and livestock and to manage sport hunting without endangering these vulnerable species. One possibility would be to restrict sport hunting to older males whose offspring have matured.
"We need to develop scientifically-based strategies that benefit hunters, livestock owners and conservationists," Packer says. "It's important to educate the public about the risks these large predators pose to rural communities and to help hunters and wildlife managers develop methods to sustain healthy populations."
"Packer's colleagues included co-authors Luke Hunter, Executive Director of Panthera and Kristin Nowell from the International Union for the Conservation of Nature Species Survival Commission (IUCN/SSC) Cat Specialist Group, as well as Dave Garshelis, Chair of the IUCN/SSC Bear Specialist Group."
Journal reference:
Packer C, Kosmala M, Cooley HS, Brink H, Pintea L, et al. Sport Hunting, Predator Control and Conservation of Large Carnivores. PLoS ONE, 4(6): e5941 DOI: 10.1371/journal.pone.0005941
Adapted from materials provided by University of Minnesota, via EurekAlert!, a service of AAAS.

Biologist Discovers Pink-winged Moth In Chiracahua Mountains

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ScienceDaily (June 12, 2009) — University of Arizona biologist Bruce Walsh has identified a new species of moth in southern Arizona. Normally, this is not a big deal. The region is one of the most biologically rich areas in the country and collectors have been finding hundreds of new species for decades. This one, however, is different.

Walsh is a professor of ecology and evolutionary biology and a member of the UA's BIO5 Institute. He is best known in the science community as an authority on plant and animal breeding, having written one of the leading textbooks on the subject.
His work also spans several departments and programs, including statistics, applied math, insect science and genetics. He also teaching biostatistics in the UA Zuckerman College of Public Health and has worked with trial attorneys on interpreting DNA evidence. Collecting moths is a hobby.
His new discovery is Lithophane leeae. Walsh found it in the Chiracahua mountains east of Tucson, and reported it in the journal Zoo Keys.
Lithophane moths are members of the noctuid family, which often are dull colored. Walsh's moth, in contrast, is bright pink. He also named it after his wife, Lee, who has an affinity for the color.
Walsh discovered L. leeae while collecting one evening at Onion Saddle, at about 7,700 feet in the Chiracahuas. Collecting involves illuminating a sheet with mercury vapor lamps. Moths are attracted by the lights and will land on the sheet.
"This large moth flew in and we didn't think much of it because there is a silk moth very much like it, a Doris silk moth that feeds on pines that has dark wings with pink on the hind wings. It's fairly common there."
On closer inspection, though, the moth, a female, appeared to be an entirely different species from an entirely different family. Walsh said it currently is the only known individual.
Scientists are generally reluctant to identify a new species based on one individual, but L. leeae appears so distinct from others that Walsh said it is highly unlikely that it is an aberration of an existing species. A DNA barcode later confirmed it as a distinct species.
Walsh said he is confident there are bound to be more. "If this thing is flying at the top of the Chiracahuas, it's probably pretty common," he said.
Finding it is another matter because moths like Lithophane tend to over-winter at higher elevations, hibernating when there is snow on the ground and flying off at the first signs of spring. Walsh said bats are the primary predators of moths, and so if the insects can make it through the winter, when bats hibernate, they will likely do well as the weather gets warmer.
As to why L. leeae hasn't been found before, Walsh theorized that his specimen simply emerged late from hibernation when it was caught. Another theory is that it could be a stray from another mountain range in the region. He said there are a number of species that fly early in the summer and are rare in collections and not often seen in most years.
"We can now add L. leeae to this group of large, but quite elusive, species," he said.
Adapted from materials provided by University of Arizona.

Close Social Ties Make Baboons Better Mothers, Study Finds

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ScienceDaily (June 11, 2009) — Baboons whose mothers have strong relationships with other females are much more likely to survive to adulthood than baboons reared by less social mothers, according to a new study by researchers at UCLA, the University of Pennsylvania and other institutions.

"If you're a baboon, the strength of your mother's relationship with other females is the best predictor of whether you'll live to have children yourself," said Joan Silk, the study's lead author and a UCLA professor of anthropology. "The study adds to mounting evidence of the biological benefits of close relationships among females."
The findings are significant because "survivorship to reproduction is the gold standard in evolutionary biology," said co-author Dorothy Cheney, a professor of biology at the University of Pennsylvania. "Females who raise offspring to a reproductive age are more likely see their genes pass along, so these findings demonstrate an evolutionary advantage to strong relationships with other females. In evolutionary terms, social moms are the fittest moms — at least when it comes to baboons."
The study appears online in the Proceedings of the Royal Society B, a peer-reviewed journal published by the national academy of science of the United Kingdom and the Commonwealth.
Silk, Cheney and seven other researchers from the University of Pennsylvania, the University of Michigan and the University of St. Andrews in Kenya analyzed 17 years worth of records on more than 66 adult female baboons in the Moremi Game Reserve, a 2,000-square-mile national park in Botswana that teems with wildlife.
Collected on the ground by primatologists who tracked the baboons six days a week, 12 months a year, the records reflected the sex and survival rates of baboon offspring, as well as telling details of the mothers' social lives, including their ranking within the group, as measured by the direction of approach/retreat interactions, and the amount of social interactions they had with each of the group's other females.
In addition to showing how often one animal approached another, the records of social interactions included details of grooming, which is known to be the primary form of social interaction in Old World monkeys. The researchers noted how much time — frequency and duration — the females spent grooming each other and how often they solicited grooming from other females.
Of all the factors studied, the strength of a mother's social bonds with another female had the most significant effect on the survival rates of offspring. A mother's dominance rank proved to have no affect on the survival rate of her offspring.
"We really expected dominance status to be more influential than it proved to be," Silk said.
Offspring from the most social mothers turned out to be about one-and-a-half times more likely to survive to adulthood than offspring from the least social mothers.
The strongest social bonds were measured between mothers and adult daughters, followed by sisters and all other potential relationships, including aunts, nieces, cousins and baboons with no familial ties. Bonds between mothers and adult daughters proved to be three times stronger than those between sisters and 10 times stronger than relationships with other females.
"What really matter to these girls are mother-daughter bonds," Silk said. "They're really strong, and they last forever. If your mom is alive, she's one of your top partners, always. But more importantly, it's the strength of these bonds, because females whose bonds with their mothers and daughters were strong had higher offspring survival than females whose bonds with these relatives were weak."
Silk's past research with Jeanne Altmann, the Eugene Higgins Professor of Ecology and Evolutionary Biology at Princeton University, and Susan C. Alberts, a professor of biology at Duke University, on baboons in the Amboseli Basin of Kenya had found a higher survival rate for baboons with social mothers, but the research only tracked offspring through the first year of life.
For the new study, researchers followed offspring from 1 year of age through sexual maturity — roughly 5 years of age. The new study also differs from past baboon research by focusing on the strength and duration of relationships between pairs of females rather than on the amount of social interactions in general.
"The benefit comes not from being wildly social — it's about having close social bonds," said Cheney, who runs the Moremi baboon-tracking project with University of Pennsylvania psychology professor Robert M. Seyfarth.
"These females form strong relationships with particular partners," Silk said. "They don't treat everyone the same. They spend a lot more time with — and a lot more time grooming — some females than others, and these relationships tend to be very long-lasting."
Additional research is needed to determine how the female bonds improve infant survival, but it may have to do with such stress hormones as cortisol, Silk said. Research has shown that prolonged elevations of stress hormones in primates can lead to cardiovascular disease and other serious health problems. Research has also shown that grooming tends to lower these stress hormones in baboons.
"Our research suggests that somehow there is a link between the kind of social relationships you form and the natural, normal stresses that occur in everyday life, and that seems to have — at least in baboons — a long-term effect on reproductive success," Silk said.
Said to share 92 percent of their DNA with humans, baboons are close relatives of humans. Baboons and humans last shared a common ancestor about 18 million years ago. The new findings on social interactions among mothers parallel recent research that has shown health benefits for humans who enjoy particularly close social networks.
"Our findings suggest benefits from forming close relationships are built into us from a long way back," Silk said.
The research received funding from the National Geographic Foundation, the Research Foundation of the University of Pennsylvania, the Institute for Research in Cognitive Science at the University of Pennsylvania, the National Institute of Health and the National Science Foundation.
Adapted from materials provided by University of California - Los Angeles.

Female Water Striders Expose Their Genitalia Only After Males 'Sing'

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ScienceDaily (June 11, 2009) — Chang Seok Han and Piotr Jablonski at Seoul National University, Korea have found that by evolving a morphological shield to protect their genitalia from males' forceful copulatory attempts, females of an Asian species of water strider seem to "win" the evolutionary arms race between the sexes. Instead, females only expose their genitalia for copulation after males produce a courtship "song" by tapping the water surface.

150 years after the publication of Charles Darwin's On the Origin of Species, Han and Jablonski used common insects, water striders, to study the intricacies of evolutionary conflict between males and females. The mechanisms for the way Darwinian natural selection, acting separately on males and females, result in different traits in males than in females (for example, different body sizes to guarantee the highest number of offspring during an individual's lifetime) are already quite well understood.
Sometimes, however, a behavioral trait, such as mating frequency, depends on both the male and the female characteristics. Natural selection favors higher mating frequency in males than in females in many animals, including humans. This leads to an evolutionary "arms race" where males evolve adaptations that force females to mate, while females evolve defenses against males' attempts.
As in the arms races between countries and political powers, it is rare for one sex to "win" in this evolutionary race.
However, in the study by Han and Jablonski, carried out at the Laboratory of Behavioral Ecology and Evolution at Seoul National University, females of an Asian species of water striders, Gerris gracilicornis, do seem to win this race as they have evolved a morphological shield behind which their genitalia are hidden from males, protecting them against the males' forceful attempts to mate.
In an apparent response to the female adaptation, after the violent mounting onto the female's back (typical in water striders), males of this species produce courtship signals by tapping the water surface with their middle legs. It is only after receiving the male's "song" that females expose their genitalia for copulation
Journal reference:
Han et al. Female Genitalia Concealment Promotes Intimate Male Courtship in a Water Strider. PLoS ONE, 2009; 4 (6): e5793 DOI: 10.1371/journal.pone.0005793
Adapted from materials provided by Public Library of Science, via EurekAlert!, a service of AAAS.

Temporary Infidelity May Contribute To Stability Of Ancient Relationships

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ScienceDaily (June 1, 2009) — Fungus-farming ants have cultivated the same fungal crops for 50 million years. Each young ant queen carries a bit of fungus garden with her when she flies away to mate and establish a new nest. Short breaks in the ants' relationship with the fungus during nest establishment may contribute to the stability of this long-term mutualism, according to a study at the Smithsonian Tropical Research Institute in Gamboa, Panama.

"We were struck by the paradox that even though the ants transfer a single fungal strain from generation to generation, nests of different ant species, and even genera, throughout Central America share genetically very similar fungi, indicating that there are exchanges going on between fungi from different nests," said Michael Poulsen, who held a Smithsonian short term fellowship while a doctoral student at the University of Copenhagen. "In these experiments, we found that there is a very short window of time--as the young queen establishes a new nest--when partner switching can occur."
Ants in the genus Acromyrmex cultivate a single fungal species in their nests: Leucoagaricus gonglyophorus. Mature ant colonies contain one fungal clone--a single genotype, which uses several strategies to make sure that other fungi do not invade.
Researchers noticed that several queens from different colonies sometimes start nests very close together and wondered if young queens were given fungi from a nest other than their natal nest—would they treat it as their own fungal crop?
"That's exactly what happens," said Poulsen, now research associate at the University of Wisconsin. "Young queens adopt a fungus from another nest and cultivate it in their new nest. This sort of temporary partner switching probably acts as an evolutionary safety net in the ant-fungus mutualism by preventing the accumulation of deleterious mutations."
The study, published in the journal Evolution, was supported by The Smithsonian Tropical Research Institute, the Lundbeck Foundation, the U.S. National Science Foundation and the Danish National Research Foundation. Panama's National Environmental Authority (ANAM) issued permits.
Journal reference:
Michael Poulsen, Hermógenes Fernández-Marín, Cameron R. Currie, Jacobus J. Boomsma. Ephemeral Windows Of Opportunity For Horizontal Transmission Of Fungal Symbionts In Leaf-cutting Ants. Evolution, 2009; DOI: 10.1111/j.1558-5646.2009.00704.x
Adapted from materials provided by Smithsonian Tropical Research Institute, via EurekAlert!, a service of AAAS.

Communal Stomach Of An Ant Colony

SOURCE

ScienceDaily (May 11, 2009) — How do ant colonies manage the nutrients in their food? Audrey Dussutour from the Centre de recherche sur la cognition animale (CNRS/Université Paul Sabatier) and Steve Simpson from Sydney University have shown that an ant colony functions like a “collective mouth and gut”. The members of a colony are capable of dealing with the nutritional needs of their social structure by sharing tasks (foraging, digestion and excretion).

In an ants' nest, food is brought home by only 10% of the colony members - the foragers. This food is then regurgitated and shared among all the ants in the colony. Nutritional needs differ, however, between the young (larvae) and adults of the colony.
Audrey Dussutour and Steve Simpson have recently shown that the larvae, which cannot move or leave the nest, are capable of communicating their nutritional needs to forager ants, who adapt their gathering strategy accordingly. These researchers provided sugar- or protein-rich foods for ant colonies with and without larvae, and observed that ant behaviour differed. When a colony had larvae, high protein foods were preferentially gathered that could sustain larval growth. Inversely, when there were no larvae, the ants preferentially gathered sugar-rich foods.
In a second experiment, the researchers showed that sugar is the key nutrient regulating gathering in ants. Provided with a range of food containing varying proportions of protein and sugar, foragers are capable of harvesting the same quantity of sugar. These researchers also observed that when the food was rich in protein and poor in sugar, the excess of proteins was ejected from the nest. Ants are therefore capable of extracting sugar from food and regurgitating protein in the form of waste pellets.
However, despite this food manipulation, the colonies reared with protein-rich food had extremely high mortality due to protein toxicity and suffered losses of up to 75%. In comparison, the ant colonies reared on food of lower protein content lost less than 5% of their numbers.
The scientists noticed that the mortality was lower in colonies with larvae. They demonstrated that the ants in these colonies managed to partially escape the toxic effects of proteins by giving the work of nutrient processing to the larvae, which are better equipped for protein digestion. The researchers also confirmed the highly toxic effect of protein-rich food on ants, as they had previously demonstrated in fruit flies.
Journal reference:
Dussutour et al. Communal Nutrition in Ants. Current Biology, May 12, 2009; DOI: 10.1016/j.cub.2009.03.015
Adapted from materials provided by CNRS.

US-Russia Polar Bear Treaty Ratified

Source:

http://www.sciencedaily.com/releases/2007/10/071014202952.htm

Science Daily — The US and Russia have ratified a bilateral agreement for the long-term conservation of shared polar bear populations in Alaska, the US and Chukotka, Russia.

The treaty unifies US and Russian management programmes that affect this shared population of bears. Notably, the treaty calls for the active involvement of native people and their organizations in future management programmes. It will also enhance such long-term joint efforts as conservation of ecosystems and important habitats, harvest allocations based on sustainability, collection of biological information, and increased consultation and cooperation with state, local, and private interests.
"WWF is pleased that this treaty will finally go into effect and formalize the increasing cooperation between US and Russian management agencies, scientists, and native communities in an effort to conserve our shared population of polar bears," said Margaret Williams, director of the WWF Bering Sea-Kamchatka Ecoregion Programme.
“With the rapid decline of arctic sea ice, now more than ever, we need to work together to ensure that polar bears have a chance to survive difficult times ahead."
Polar bears typically occur at low densities over vast areas of the Arctic. Current estimates of the world's 19 separate populations range from 20,000 to 25,000 bears. Two populations of the bears occur in Alaska: the southern Beaufort Sea population (about 1,500 animals), shared with Canada; and the Alaska-Chukotka (Chukchi Sea) population (approximately 2,000 bears), which is shared with Russia.
"While we are very pleased the treaty is coming into effect and support its goals, we urge the US government to take more courageous and bold actions to address the factor now widely recognised as the source of global climate change and resulting warming in the polar bears' arctic habitat: CO2 emissions," Williams added.
The treaty fulfills the spirit and intent of the 1973 multilateral Agreement on the Conservation of Polar Bears among the United States, Russia, Norway, Denmark (for Greenland) and Canada by allowing a sustainable harvest by Alaska and Chukotka natives, but prohibiting the harvest of females with cubs or of cubs less than one year old. It also prohibits the use of aircraft and large motorized vehicles in the taking of polar bears and enhances the conservation of specific habitats such as feeding, congregating, and denning areas.
Note: This story has been adapted from material provided by World Wildlife Fund.

Fausto Intilla

www.oloscience.com

No Faking It, Crocodile Tears Are Real

Source:

http://www.sciencedaily.com/releases/2007/10/071003151131.htm

Science Daily — When someone feigns sadness they “cry crocodile tears,” a phrase that comes from an old myth that the animals cry while eating.

Now, a University of Florida researcher has concluded that crocodiles really do bawl while banqueting – but for physiological reasons rather than rascally reptilian remorse.
UF zoologist Kent Vliet observed and videotaped four captive caimans and three alligators, both close relatives of the crocodile, while eating on a spit of dry land at Florida’s St. Augustine Alligator Farm Zoological Park.
He found that five of the seven animals teared up as they tore into their food, with some of their eyes even frothing and bubbling.
“There are a lot of references in general literature to crocodiles feeding and crying, but it’s almost entirely anecdotal,” Vliet said. “And from the biological perspective there is quite a bit of confusion on the subject in the scientific literature, so we decided to take a closer look.”
Vliet said he began the project after a call from D. Malcolm Shaner, a consultant in neurology at Kaiser Permanente, West Los Angeles, and an associate clinical professor of neurology at the University of California, Los Angeles.
Shaner, who co-authored the research paper*, was investigating a relatively rare syndrome associated with human facial palsy that causes sufferers to cry while eating. For a presentation he planned to give at a conference of clinical neurologists, he wanted to know if physicians’ general term for the syndrome, crocodile tears, had any basis in biological fact.
Shaner and Vliet uncovered numerous references to crocodile tears in books published from hundreds of years ago to the present.
The term may have gained wide popularity as a result of a passage in one book, “The Voyage and Travel of Sir John Mandeville,” first published in 1400 and read widely, they write.
Says the passage, “In that country be a general plenty of crocodiles …These serpents slay men and they eat them weeping.”
Shaner and Vliet also found reference to crocodiles crying in scientific literature, but it was contradictory or confusing, to say the least.
One scientist, working early last century, decided to try to determine if the myth was true by rubbing onion and salt into crocodiles’ eyes. Shaner said. When they didn’t tear up, he wrongly concluded it was false. As Shaner said, “The problem with those experiments was that he did not examine them when they were eating. He just put onion and salt on their eyes.”
As a result, Vliet decided to do his own observations.
In the myth, crocodiles often cry while eating humans. However, deadpanned Shaner, “we were not able to feed a person to the crocodiles.”
Instead, Vliet had to settle for the dog biscuit-like alligator food that is the staple at the St. Augustine alligator farm. He decided to observe alligators and caimans, rather than crocodiles, because they are trained at the farm to feed on dry land. That’s critical to seeing the tearing because in water the animals’ eyes would be wet anyway.
The farm’s keepers don’t train the crocodiles to feed on land because they are so agile and aggressive, Vliet said. But he said he feels sure they would have the same reaction as alligators and caimans, because all are closely related crocodilians.
What causes the tears remains a bit of a mystery.
Vliet said he believes they may occur as a result of the animals hissing and huffing, a behavior that often accompanies feeding. Air forced through the sinuses may mix with tears in the crocodiles’ lacrimal, or tear, glands emptying into the eye.
But one thing is sure: faux grief is not a factor. “In my experience,” Vliet said, “when crocodiles take something into their mouth, they mean it.”
*A paper about the research appears in the latest edition of the journal BioScience.
Note: This story has been adapted from material provided by University of Florida.

Fausto Intilla

www.oloscience.com

Enormous Spider Web Found In Texas

Source:

http://www.sciencedaily.com/releases/2007/09/070912145919.htm

Science Daily — An arachnaphobe’s worst nightmare, the gauzy, insect-laden web drew more than 3,300 curious visitors over the three-day holiday to this 376-acre park on the shore of Lake Tawakoni, 50 miles east of Dallas. On Labor Day, the park recorded 1,275 people visiting just to see the web.

“When I first saw it,” said Park Superintendent Donna Garde, “I was totally amazed. What ran through my mind was that this looked like something out of a low-budget horror movie, but I was looking at something five times as big as what you’d see on a Hollywood set.”
Stumped as to the web’s origin, the initial consensus of arachnologists and entomologists who saw an online photo of the web sent by Texas Parks and Wildlife Department biologist Mike Quinn was that it may have resulted from a “mass dispersal” event. In such an event, millions of tiny spiders or spiderlings spin out silk filaments to ride air currents in a phenomenon known as “ballooning.”
Quinn collected a sample of spiders Aug. 31 from in and around the gigantic web and took them to Texas A&M University in College Station for analyses. Entomology Department researcher Allen Dean identified 11 spider families from the sample. The most prevalent species was the Tetragnatha guatemalensis, or what Quinn dubbed the Guatemalan long-jawed spider, since this species didn’t have a common name. Guatemala was the country in which it was first documented.
“I drove 50 to 100 spiders to A&M on Saturday,” Quinn said. “Spider experts tend to specialize in one or few families of spiders. There are nearly 900 species of spiders known from Texas, so no one is an expert on all the species.”
Quinn described the Lake Tawakoni web as “sheet webbing” since it covers a large area of trees, which is more typical of a web spun by a funnel web spider rather than the classic Charlotte’s web, or orb web, like that produced by long-jawed spiders. He speculates that the park’s spider population exploded due to wet conditions this summer that resulted in an abundance of midges and other a small insects upon which the spiders feed.
The Guatemalan long-jawed spider ranges from Canada to Panama, and even the islands of the Caribbean. According to Quinn, the spider is about an inch in length with a reddish-orange head- and-thorax. Spiders, like mites and scorpions, are arachnids, a group of arthropods with four pairs of legs, saclike lungs and a body divided into two segments.
So popular was the monster Lake Tawakoni spider web phenomenon that it ran as the lead story in the Nation section of the Aug. 31 New York Times, and was the newspaper’s most e-mailed article that day. The nightmarish quality of the story prompted satirical takes on several Internet Web sites and led to national coverage on Fox News, the Discovery Channel, CNN and other networks. Quinn termed the degree of news coverage “remarkable.”
Dr. Norman Horner, a retired dean of the College of Science and Mathematics at Midwestern State University in Wichita Falls, was on his way to the park mid-week to study the “not very common” phenomenon, when he received a call from park staff telling him that a heavy overnight rainstorm had made the trail impassable and knocked down much of the giant web.
“So far,” Horner said, “we have been informed of webs of this nature occurring in Florida, California, Canada, Italy, Ohio and now Texas. In all cases, they appear to have been produced by tetragnathids, but have other species associated with them.”
Superintendent Garde said Sept. 5 that the crowds coming to see the wondrous creation had slowed to a trickle, and that they were not being allowed to access the nature trail due to the sloppy conditions.
“It was fun, but we were really tired,” Garde said. “The spiders are great little guys. They put our park on the map.”
Note: This story has been adapted from a news release issued by Texas A & M University.

Fausto Intilla

www.oloscience.com

Ecologists Get To The Bottom Of Why Bears Rub Trees

Source:

http://www.sciencedaily.com/releases/2007/09/070909221303.htm

Science Daily — Ecologists have at last got to the bottom of why bears rub trees – and it's not because they have itchy backs. Speaking at the British Ecological Society's Annual Meeting in Glasgow the week of September 10, Dr Owen Nevin of the University of Cumbria will reveal that adult male grizzly bears use so-called “rub trees” as a way to communicate with each other while looking for breeding females, and that this behaviour could help reduce battles between the bears.

Many theories have been advanced as to why bears rub trees: some thought females might rub trees as they came into oestrous, and others that bears might be giving their backs a good scratch to get rid of parasites or pick up sap to act as insect repellent. Until now these ideas have been extremely difficult to test because bears usually live at low densities and rubbing is relatively rare behaviour.
Because bears use the same rub trees for generations, and because he has logged rub trees over almost a decade working on bears in British Columbia in Canada, Nevin has been able to gain a unique insight into grizzlies' behaviour. Over the past two years, he used four digital cameras with infra-red trips set up opposite rub trees to collect data on which bears used the trees and when. He coupled this with satellite telemetry equipment to track individual bears' movements.
“The cameras show that adult male bears are the most likely to rub trees, and the satellite telemetry tells us that males move from valley to valley in large loops, marking trees as they go, while looking for breeding females,” Nevin says.
Nevin believes that by marking trees, adult males may be getting to know each other better, and that this scent familiarity could act as a way of reducing fighting among adult male bears. According to Nevin: “Big male bears can seriously injure and even kill each other when they get into a fight. If one recognises the other from the scent marks on the rub trees in the area he knows he’s in for a tough fight - he’s on the other guy’s patch so to speak - so it might be better to back away than make a serious challenge.”
Like other species, male bears will sometimes kill a female’s offspring to get a chance to mate with her; scientists refer to this as sexually-selected infanticide. Nevin’s work suggests that very young bears may be using the rub trees to help them trick potentially killer males.
“It’s really hard to document, but on several occasions the cameras caught cubs who are being chased away from their mother by a large male visiting and rubbing on trees which he has marked. They can visit the tree two or three times in a day, sometimes within an hour of the big male, so it may be that smelling like him makes them safer – related animals smell similar and animals are less aggressive towards relatives,” Nevin says.
As well as improving our understanding of how bears communicate, the results should also help improve bear conservation by affording an insight into the behaviour of secretive male bears. Earlier work in Canada and Alaska has shown that tourist activities can change how adult male bears behave during the autumn salmon-feeding season, which has been the focus of eco-tourism, but spring viewing when the bears are breeding is becoming increasingly popular.
According to Nevin: “Understanding normal behaviour has to be the starting point for managing bear populations and our activities around them. It doesn’t matter whether we’re considering impacts of tourism or sport hunting on these dense North American populations or reintroductions and enhancements in threatened European populations: knowing how these animals interact with each other will help us to make the right decisions.”
Dr Nevin will present his findings on Monday 10 September 2007 at the British Ecological Society Annual Meeting.
Note: This story has been adapted from a news release issued by British Ecological Society.

Fausto Intilla

www.oloscience.com

Humpback Whales Recorded Clicking And Buzzing While Feeding For First Time

Source:

http://www.sciencedaily.com/releases/2007/09/070901084549.htm

Science Daily — For the first time, researchers have recorded “megapclicks” — a series of clicks and buzzes from humpback whales apparently associated with nighttime feeding behaviors — in and around NOAA’s Stellwagen Bank National Marine Sanctuary.

As detailed in the most recent issue of the Royal Society journal Biology Letters, this study offers the first documentation that baleen whales produce this type of sound, normally associated with toothed whales and echolocation.
“We’ve known that humpback whales exhibit a variety of foraging behaviors and vocalizations, but these animals as well as other baleen whales were not known to produce broadband clicks in association with feeding,” said David Wiley, sanctuary research coordinator and leader of the research team. “However, recent work with special acoustic tags has made us reexamine our previous assumptions, with this expansion of the acoustic repertoire of humpback whales.”
The research team from the Hawaii Institute of Marine Biology, Woods Hole Oceanographic Institution, University of New Hampshire, and NOAA’s National Marine Sanctuary Program used multi-sensor acoustic tags attached with suction cups to study whale behavior. The data provided a record of the whales’ underwater movements, including heading, pitch, roll, and sounds made and heard. During the tagging studies, broadband clicks were recorded exclusively during nighttime hours. Sharp body rolls also occurred at the end of click bouts containing buzzes, suggesting feeding episodes.
Alison Stimpert of the Hawaii Institute of Marine Biology, the lead author on the paper, labeled the sounds “megapclicks” based on their form and the scientific name for humpback whales (Megaptera novaeangliae). This acoustically active species has been known to produce complex “songs” on their breeding grounds, but knowledge of sound production on northern feeding grounds has been limited.
The researchers report that the similarity of the megapclicks to sounds made by toothed whales suggests echolocation-assisted feeding behaviors, especially where buzzes at the end of a series of clicks appear to be associated with attempts to capture prey. The sounds may also be used to detect the sea floor or other large targets. Another possibility for the megapclicks could be to attract prey, such as herding schools of fish or chasing animals out of the sediments. But the research team notes that a lack of knowledge about baleen whale hearing and sound production prevents any definitive answers at this time about the function of the megapclicks.
Additional humpback whale tagging studies completed earlier this summer in the Stellwagen Bank sanctuary may provide further insights into sound production in northern feeding grounds.
The report appeared in the Aug. 8, 2007 on-line issue of Biology Letters. Funding for the project was provided by NOAA’s National Marine Sanctuary Program and the University of Hawaii Sea Grant College Program. Research was conducted under National Marine Fisheries Service permit no. 981-1707-00.
Recordings of clicking and buzzing whales can be found here. http://stellwagen.noaa.gov/pgallery/sounds.html
Note: This story has been adapted from a news release issued by National Oceanic & Atmospheric Administration.

Fausto Intilla

www.oloscience.com